praetexta

or pre·tex·ta

[ pree-tek-stuh ]
/ priˈtɛk stə /

noun, plural prae·tex·tae [pree-tek-stee] /priˈtɛk sti/.

(in ancient Rome) a white toga with a broad purple border, worn by priests and magistrates as an official costume, and by certain other Romans as ceremonial dress.
a similar garment worn by a boy until he assumed the toga virilis, or by a girl until she married.

Origin of praetexta

1595–1605; < Latin, short for toga praetexta literally, bordered toga. See pretext